DRUM WICKETS AND SEAR-TRAPS. 



263 



Lang Gates. Sandy Lake Reservoir, Minnesota, built in 1895. One gate u feet 

 long, 12 feet high; two gates used as lock-gates, each 40 feet long and 13 feet high, 

 made of wood. 



BEAR TRAP GATEG. 



f ffECTCO IN THE UPPER CHAMBEH, OLD LOCK* 



LOUISIV1LLE AND PORTLAND CANAL. 



SCALE OF INCHES 



-A DETAILS AT "B" 



SECTION "F-F" 



PLAN. ELEVATION AND SECTION OF HOLLOW QUOIN 



: I 



DETAILS AT "A' 

 BEAR-TRAP AT LOUISVILLE. KY., 1896. (DIRECT PARKER TYPE.) 



Old Bear- trap Gates. Two of this type are under construction on the movable 

 dams of the upper Ohio, each with a length of 120 feet and a height of 13 feet 2 inches. 



Calculations. To determine the dimensions of the old-style two-leaved and of the 

 Parker bear-trap, the following data have been deduced * (Fig. 23) : 



OLD BEAR-TRAP. 



Let X be the length of the up-stream leaf ; 



Y the length of the down-stream leaf ; "*" 

 Z the overlap of the two leaves ; 

 PI the downward pressure ; 

 P 2 the upward pressure ; 

 It the difference of level between the 

 entry and the exit of the operating flume, and w the weight of a cubic foot of water. 



* Journal of th^ Aso'iation of E-Tjincerinc; So-ic-ties, June, 1896, from n paper submitted by the Civil 

 Engineers' Society of St. Louis, by Captain H. M. Chittendcn, U. S. A., and Mr. Archibald O Powell. The 

 accompanying curves arc reproduced by permission from the same paper. 



FlG - 



